A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-00-367-2706
NSN 6150-00-231-9434
NSN 6320-00-089-9426
NSN 5998-01-381-2190
NSN 5965-01-137-3769
NSN 5945-01-010-7434
NSN 6130-01-099-4950
NSN 5950-01-628-1873
NSN 5965-01-267-3812
NSN 5999-01-547-7509
NSN 6130-00-305-1052
NSN 6685-01-119-8156